SHI International: $4.5 Billion

SHI International (formerly known as Software House International) is an online marketplace where enterprises can buy tech like computers, printers, servers, and so on. It also sells consulting services and cloud computing.

At $4.5 billion in revenue (according to a company's spokesperson) and with over 2,000 employees, SHI is the one of the largest minority and woman-run tech businesses in the nation.

Infor: $2.8 billion

Infor is has quietly become a huge enterprise app company, with around $3 billion in sales and an estimated valuation of $16.1 billion.

Its CEO knows software. He is ex-Oracle president Charles Philips. One of the reasons Infor stays under the radar is that it has grown by acquisitions, so it's like a collection of smaller software companies. Each of them serves a very specific business niche, like dairies or footwear companies.

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Zones: $1 Billion

Zones is a "value-added-reseller," meaning it sells computer hardware, software, and equipment to businesses, and then helps them install and maintain it. It specializes in complex stuff like Cisco networking and virtualization tech.

Its CEO is an interesting guy. Uganda-born Lalji was the founder of the retail store chain Kit Cameras, which he sold in 1997, right before he took on the CEO job at Zones.

PayPros: $214 million

PayPros (formerly called Payments Processing) is a company that sells payments processing software and point-of-sale software, the software that powers cash registers and other terminals businesses use to take money. It's got over 55,000 customers.

Urban Science: $125 million

Urban Science offers business analysis software for auto makers worldwide. It was founded in 1977 when Anderson was a professor at Wayne State University. He came up with a way for Cadillac to do sophisticated, math-and-science-based marketing. It's sort of like "Moneyball" for cars. (Yes, we're referring to the Brad Pitt movie about the Oakland A's.) Anderson has been its leader for 35 years.

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Ahead: $125.3 million

Ahead is a tech service company that describes itself as "a collective brain of technologists and consultants." It helps enterprises deploy the latest, greatest tech for their networks and data centers.